To obtain a desired realism, many flight simulators, particularly those for fighter and attack aircraft, use visual systems. Such visual systems include an image generation system, e.g., a motion picture projector or computer image generator (CIG) combined with an image display subsystem, e.g., cathode ray tubes (CRTs) or a light valve projector and screen.
For maximum training capability, such visual systems should allow a trainee to see over a wide field of view. Further, the trainee should be able to search for hidden targets and other objects within the field of view, and discriminate one object from another. In effect, the visual system should provide high detail scene content with high resolution of that scene content, throughout the entire field of view.
It is impossible, however, in today's state of the art, to provide a visual system that has these capabilities. Power and bandwidth requirements, as well as cost, for example, preclude using such visual systems in a flight simulator. Recognizing these limitations, the prior art has attempted to work around them by accepting compromises in image generation and/or image display.
A major deficiency of some of the prior art visual systems has been that they conspicuously define or present an object within the field of view. This prevents the trainee from arbitrarily discriminating among similar scene elements or similar targets, as in the real world tactical situation.
For example, some image generation systems provide an austere environment over a wide field of view, at the same time providing high detail and high resolution for particular objects within the field of view. These particular objects thus "stand out" in an unrealistic fashion. This may be called an "oasis of detail" problem.
Other visual systems employ more powerful image generation systems, but present an "oasis of resolution" problem. Here, the background scene content or detail will be greater over the entire field of view. Thus particular objects can be made to blend with the high detail background from the standpoint of image detail. However, if particular objects are presented with a superior resolution with respect to the surrounding high detail background, then an "oasis of resolution" will be created which will catch the trainee's attention in an unrealistic fashion, and prevent him from discriminating objects.
The "oasis of detail" problem and the "oasis of resolution" problem suggest that a need exists for an improved visual system. The present invention provides a visual system that addresses the cited problems and improves upon the prior art visual system by providing high detail scene content with high resolution wherever a trainee is looking throughout a wide field of view. The present invention thus allows the construction of a visual system that eliminates the "oasis of detail" and "oasis of resolution" problems. The apparatus of the present invention provides the desired realism that enables a trainee to interpret varied, complex, and frequently subtle visual cues.